NexGard vs Sentinel

In the realm of pet health, parasite prevention is paramount. There’s a host of parasitic diseases that can affect our furry friends, making it essential to use high-quality preventive treatments. Two such treatments in discussion today are NexGard and Sentinel, both well-known brands offering protection against a range of parasites. But which one should you choose for your beloved pooch?

What is NexGard?

NexGard is a chewable tablet that provides broad-spectrum coverage for parasites in dogs. It’s known for being effective against fleas and ticks, including the Lone Star Tick, Black-legged Tick, American Dog Tick, and Brown Dog Tick. Moreover, NexGard can kill adult fleas before they have a chance to lay eggs, helping to prevent infestations.

NexGard: Pros and Cons


  • Provides a full month of protection
  • Beef-flavored chew makes administration easy
  • Kills fleas before they can lay eggs
  • Kills various types of ticks


  • Not safe for puppies under 8 weeks old
  • Side effects can include vomiting, dry/flaky skin, diarrhea, lethargy, and lack of appetite
  • Does not prevent heartworm disease or intestinal parasites

What is Sentinel?

Sentinel is a monthly oral preventive that guards against heartworms, adult roundworms, adult hookworms, whipworms, and prevents the development of flea eggs. It operates by interrupting the life cycle of these parasites, but does not kill adult fleas or ticks.

Sentinel: Pros and Cons


  • Provides broad-spectrum protection against various internal parasites
  • Controls flea populations by preventing flea eggs from hatching
  • Can be used in puppies as young as 4 weeks


  • Does not kill adult fleas or ticks
  • Some dogs may exhibit reactions, including vomiting, diarrhea, decreased appetite, lethargy, and hypersensitivity reactions

NexGard vs Sentinel: The Verdict

The choice between NexGard and Sentinel ultimately depends on your pet’s needs and lifestyle. If your pet is more exposed to ticks and fleas, NexGard may be more appropriate due to its direct killing action. However, if heartworm and intestinal parasites are more of a concern, Sentinel provides broad-spectrum coverage.

Remember, Sentinel and NexGard can be used concurrently for maximum protection, as they target different parasites. Always consult with your veterinarian before making any changes to your pet’s preventive care regimen. They will consider your dog’s health status, age, weight, and lifestyle before recommending the most suitable treatment.

Frequently Asked Questions

1. How do NexGard and Sentinel work?

NexGard contains the active ingredient afoxolaner, which interferes with the nervous system of parasites, leading to their death. It is specifically effective against adult fleas and several species of ticks, providing a full month of protection with each dose.

Sentinel, on the other hand, is a combination product that contains milbemycin oxime and lufenuron. Milbemycin oxime prevents heartworm disease and controls adult hookworm, roundworm, and whipworm infections. Lufenuron is an insect growth regulator that interrupts the flea life cycle by preventing flea eggs from hatching, thereby controlling flea populations.

2. Can my puppy take NexGard or Sentinel?

For NexGard, the minimum age and weight for administration are 8 weeks and 4 pounds, respectively. Conversely, Sentinel can be administered to puppies as young as 4 weeks and weighing over 2 pounds. Always consult your vet before beginning a new treatment regimen for your puppy.

3. What if my dog has a known allergy to beef?

As NexGard is a beef-flavored chewable, it might not be suitable for dogs with a known beef allergy. An alternative product or flavor might be needed. Sentinel is a pork-flavored tablet, and might be an alternative for dogs with a beef allergy.

4. Can my dog take both NexGard and Sentinel?

Yes, many vets actually recommend this combination for comprehensive protection. NexGard tackles fleas and ticks, while Sentinel covers heartworms and other intestinal parasites, as well as preventing the development of flea eggs. This way, your dog is protected against a wide array of common parasites. Always consult your vet before combining treatments.

5. What should I do if I miss a dose?

If you miss a dose, administer the medication as soon as you remember. Don’t double up on doses; simply continue with the regular dosing schedule. It’s crucial to give these medications consistently, as gaps in protection can leave your dog vulnerable to parasitic diseases.

6. What are the potential side effects of NexGard and Sentinel?

The most common side effects of NexGard include vomiting, itching, diarrhea, lethargy, and lack of appetite. For Sentinel, side effects may include vomiting, diarrhea, decreased appetite, lethargy, and hypersensitivity reactions. If your pet experiences any adverse reactions, consult your vet immediately.

7. How effective are NexGard and Sentinel in preventing and treating parasitic infections?

Both NexGard and Sentinel have proven efficacy in preventing and treating a variety of parasitic infections. NexGard is highly effective in eliminating adult fleas and ticks, while Sentinel is crucial for preventing heartworm disease and controlling other intestinal parasites, along with breaking the flea life cycle. However, effectiveness can vary based on factors such as adherence to dosing schedules, the presence of other pets in the household, and local parasitic prevalence.

8. Can these medications be used in pregnant or lactating dogs?

For Sentinel, it’s been demonstrated to be safe in pregnant and lactating dogs when used at the recommended dose. However, the safety of NexGard in pregnant, breeding, or lactating dogs has not been evaluated. As with any medication, it’s always best to consult with your vet if your dog falls into one of these categories.

9. How quickly do NexGard and Sentinel start working?

NexGard begins to kill fleas within 4 hours of administration and ticks within 24 hours. This makes it an effective option for quick relief. Sentinel’s lufenuron component starts working immediately to inhibit the development of flea eggs, but remember that it does not kill adult fleas. Milbemycin oxime starts to eliminate intestinal worms within hours.

10. Are there any contraindications for NexGard and Sentinel?

NexGard should not be given to dogs with a known hypersensitivity to afoxolaner. Sentinel is contraindicated for dogs with a known allergy to milbemycin oxime or lufenuron. Also, dogs already suffering from, or at risk for, heartworm disease should not be given Sentinel without careful assessment and treatment planning by a vet.

11. Do I need a prescription for NexGard and Sentinel?

Yes, both NexGard and Sentinel are prescription-only medications. Your vet will need to assess your pet’s health and lifestyle to decide the best parasite prevention plan.

12. What happens if my dog ingests more than the prescribed dose?

Overdose can lead to side effects like vomiting, drowsiness, and dilated pupils (with NexGard), or salivation and muscle tremors (with Sentinel). If you suspect your dog has ingested more than their prescribed dose, contact your vet immediately or reach out to an emergency pet poison helpline.

13. What is the recommended dosage for NexGard and Sentinel?

The dosage of both NexGard and Sentinel depends on your dog’s weight. Your vet will determine the most appropriate weight category for your pet. Both medications are typically administered once a month, but the precise frequency might change based on your vet’s assessment and the local prevalence of parasites.

14. What are the possible side effects of NexGard and Sentinel?

Like any medication, NexGard and Sentinel can have side effects. Common side effects of NexGard include vomiting, dry/flaky skin, diarrhea, lethargy, and lack of appetite. Sentinel’s potential side effects include vomiting, depression/lethargy, pruritus, urticaria, diarrhea, hypersalivation, seizures, and weakness. It’s essential to monitor your dog after administering any new medication and report any adverse reactions to your vet.

15. Can puppies take NexGard and Sentinel?

NexGard can be administered to puppies from 8 weeks of age and weighing at least 4 pounds. Sentinel, on the other hand, can be given to puppies as young as 4 weeks and weighing at least 2 pounds. However, it’s always best to consult with your vet to establish the most suitable prevention and treatment plan for your puppy.

16. Can NexGard and Sentinel be used together?

Yes, NexGard and Sentinel can be used together. This combination can offer a comprehensive spectrum of protection against fleas, ticks, heartworms, and intestinal parasites. However, it’s important to discuss this with your vet to ensure it’s the right approach for your dog, given its health status and lifestyle.

17. How should I store NexGard and Sentinel?

NexGard and Sentinel should be stored at room temperature in a safe place out of reach of children and pets. They should be kept in their original packaging until it’s time to administer them.

18. Can I administer NexGard or Sentinel to my cat?

No, these medications are designed specifically for dogs and should not be given to cats or other animals. There are other products formulated for cats to prevent and treat parasites. If you need a solution for a cat, your vet can provide a recommendation.

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